This invention relates to metal buildings, particularly of the pre-engineered type comprising bolted together metal columns and beams with metal panels secured thereto. This type of building structure grew significantly in popularity during the 1950's and it possesses many advantages. For example, the building is relatively economical and may be constructed relatively quickly and easily with relatively unskilled labor. However, such buildings are relatively difficult to heat and maintain comfortably warm in cold climates.
Typical heating systems for metal buildings utilize the circulation of heated air, and in some instances, infrared heaters are used. However, it is relatively costly to heat such buildings with either of these methods, since metal buildings are generally not well insulated and large heat losses through the walls and roof of the building are experienced, and moreover, when circulated hot air is used for heating buildings, large amounts of heat are lost through open doors and the like, and considerable time is required in order to bring the temperature of the building back to comfortable levels. Infra-red heaters, on the other hand, are relatively expensive to install and require relatively large amounts of energy to operate. Additionally, with conventional heating systems extensive ductwork or plumbing and the like must be provided in the building for circulation of hot air or hot water and the like to radiators or grids provided in the building. All of these factors contribute both to the initial cost of the building and to the cost of maintaining and operating the same.
The present invention provides a unique integrated heating system with the metal building structure, wherein separate heating ducts and the like are not required, and wherein relatively small, inexpensive and efficient heating units or boilers are sufficient to maintain the temperature in the building at a comfortable level. More particularly, in accordance with the present invention a unique integrated heating system is provided, wherein a relatively small hot water boiler is connected with suitable piping, including heating grids embedded in the floor of the building, and with the heating grids connected with the support columns and roof beams of the building, and wherein the columns and roof beams are constructed with hollow interiors for circulation of hot water therethrough, such that water heated by the boiler is circulated through the columns and beams and through the grids in the floor to heat the building primarily through radiant energy to thus obtain a substantially uniform temperature throughout the interior space of the building. Moreover, with the unique heating system provided by the invention, the structural steel members of the frame of the building and the concrete floor thereof are heated and water is used as the heat exchange medium. All of these elements retain heat for a period longer than air, and accordingly, once a desired temperature is obtained, the residual heat in these elements will maintain the temperature for an extended period of time. Accordingly, operation of the heater or boiler is required only at relatively infrequent intervals, as compared with prior art systems. A further advantage of this unique heating system is that open doors and the like do not affect temperature within the building as drastically as prior art systems utilizing circulated hot air. Moreover, the metal components of the building and the floor and the like are all warm, thus adding to the comfort of the interior of the building. Still further, the unique arrangement of components of the heating system of the invention enables different areas of the building to be heated to different temperatures, to thus obtain the most comfortable and efficient temperature relationships throughout the building. For example, in some areas a lower temperature may be required for comfort than in other areas of the building, and also, the northern portion of the building or that portion thereof exposed to the more severe weather conditions may require a greater temperature input than other portions of the building to maintain a substantially uniform and comfortable temperature level throughout the building.
In fact, in a building constructed in accordance with the present invention, a boiler or heater having a capacity normally used to heat a home having approximately 2,000 square feet of living space was utilized to effectively maintain a comfortable temperature in a metal building having approximately 31,000 square feet of floor space. Moreover, with this invention it was found that during even the coldest winter months the boiler or burner only operated for approximately 4 hours out of a 24 hour period, and yet maintained adequate temperature levels. The result with the building constructed in accordance with the present invention was a savings of approximately 70% in fuel costs, along with a greater degree of comfort in the building, and in fact, it is estimated that the savings realized by the heating system of the invention will actually pay for the cost of construction of the building in approximately 10 years.